We use virgin polyester thread and polyester zipper tape in the making of our garments. We’ve chosen to use polyester because we haven’t found a thread or tape that compares in quality - it’s just a strong material. The first rule to sustainable production is: make your clothes last! Polyester thread and tape is the best way we know how, especially when tensile strength is put to the test - like with our pants. With that said, we are working extremely hard to find an alternative. We are hoping to have a limited run of either cotton or Tencel thread in our collection coming this fall! Side note: all the alpaca pieces are 100% alpaca and contain no polyester thread.